1. FIELD OF THE INVENTION
The present invention relates to a method and apparatus for determination of a simultaneous, permanent and separate recording and measurement of the head and trunk movements of a body in one plane during standing and walking. The invention includes optical markers, which are mounted upon the head and the trunk of the test person. Such an apparatus also includes a device which is stationarily put in operation at a distance above the test person, and continuously receives and records the optical signals of the markers.
2. DESCRIPTION OF THE PRIOR ART
A similar device has been used until now by means of the so-called cranio-corpo-graphy (CCG), which has been described in the literature:
"Ein einfacher, objektiver und quantitativer Gleichgewichstest fur die Praxis Forschungsbericht Cranio-CorpoGraphy (CCG), Schritfenreihe des Hauptverbandes der gewerblichen Berufsgenossenschaften eV, Lindenstrasse 78, D 5205 St. Augustin 2, West Germany, Juni 1986."
However, several disadvantages are adhered to this well-known instrument. For obtaining a sufficient distance between the test person and the optical receiver and recorder, a mirror is attached to the ceiling into which a camera is centrally directed from below. Thus, an area of loss is visibly of the optical marker is created centrally underneath the camera, within which the markers cannot be observed. Another disadvantage lies in the fact that handling the camera involves difficult overhead maneuvering. Since all the exposures can only be recorded outside of the central scotoma, distortions of the measurements occur due to parallaxes, with an increasing impact when moving towards the border of the field of observation. Since the photographic recording is two dimensional, a time critical spectral analysis of the movement patterns cannot be achieved, even though it is diagnostically important, due to the hierarchically organized central nervous movement regulation, including the brain hemispheres, brain stem and spinal cord. Finally, an analysis of the movement patterns of the various marker points upon the head and the body is impaired and partly impossible due to overlapping of the light tracings during the swaying movements of the head and body, when standing stepping or walking.
Another prior art device is described in U.S. Pat. No. 4,375,674, issued Mar. 3, 1983, for "Kinesiometric Method and Apparatus" to William E. Thawnton. Disclosed therein are an apparatus and method for the determination of functional capability of bodies. Reach, as well as velocity, acceleration and force generation at various positions, may be determined for parts of the body by a three-dimensional kinesimeter, equipped with an ergometer. This invention finds particular application to the measurement of human task performing capabilities. A three camera video position detector system is positioned equidistant around a stationary reference lamp. The test subject, whose anthropometric characteristics are to be observed, is regularly positioned within the field of view of the camera system. The test person is kept in fixed relation to the reference site by body belts, as shown in FIGS. 5 and 10 thereof. The recorder light fixed to a part of the body, for instance an arm or a hand, is then recorded through the cameras when moving. The system needs a complicated calibration procedure to be appropriately programmed with proper scale factors and locations, as well as zero references used in calculations of position for accurate dimensional measurements, in which one of the lamps serves as a reference lamp. This invention does not allow recording of locomotor tracings over the plain field of visibility, as the body must be kept close to the reference lamp. It is therefore used for establishing maximum reach envelopes. A simultaneous recording of several head and body marker points during walking consequently cannot be achieved since always only the coordinates of one marker point are put into relation with the central coordinates of the reference lamp. Also, the ergometer needs to keep the body stationary, as depicted in the figures.
A further variety of techniques, which have been developed to attempt to measure one aspect or another of human activities, have also been described and discussed in the background of the invention section of U.S. Pat. No. 4,375,674.